Nuns rally as Zubik v. Burwell, an appeal brought by Christian groups demanding full exemption from the requirement to provide insurance covering contraception under the Affordable Care Act, is heard by the US Supreme Court in Washington in March. On Monday the court sent the case back to the lower courts.

An often-divided Supreme Court issued a surprise on Monday: It paved the way for consensus and compromise.

The eight justices didn’t come to a decision in the case, which looks at how religious nonprofits should be insulated from providing contraceptives to their employees. They simply chose to send the case back to the lower courts of appeal.

But the justices did this because the plaintiffs and defendants – at the Supreme Court’s prompting – agreed to a compromise that both sides found acceptable.

Consensus-building was one of the defining characteristics of the court under Chief Justice Earl Warren in the 1950s and ’60s. Today, the court is, by some measures, more split and polarized than at any time in its history.

What has happened is a story familiar to America more broadly. In the wake of Roe v. Wade, interest groups have increasingly used the court as a way to seek victories in the culture wars. In turn, presidents have nominated more-reliable partisans to the bench.

The current court of Chief Justice John Roberts has continued and even amplified a two-decade-long trend of deciding more and more cases along strict 5-to-4 ideological lines.

But some experts say Monday’s unusual ruling offers a glimpse of a different way of operating.

Since joining in 2005, Chief Justice Roberts has talked of his desire to lift the court above partisan politics. The cultural and political forces working against such ambitions remain. But Monday’s case at least cracks the door for similar compromises in the future, says Jeffrey Rosen, a professor at the George Washington University School of Law.

“The past few months [since the death of Justice Antonin Scalia] have given the justices the experience of their power to promote compromise – their ability when they choose to work together to encourage both parties to achieve common ground that wouldn’t have previously been obvious,” he says.

The art of the deal

To be sure, Monday’s case was unique: It divided the court 4 to 4 at a time when the Republican-held Senate is refusing to consider President Obama’s nominee for Justice Scalia’s seat. It came in a case where lower courts rulings were divided – raising the need for the Supreme Court to find resolution. And the two parties involved were able to agree to common ground.

Yet that compromise came directly at the Supreme Court’s urging. Apparently worried that it would split 4 to 4 in the case, the Supreme Court suggested changing how religious nonprofits opt out of providing contraception for employees.

Under Obamacare, the nonprofits had to send a note to their insurers saying they would not cover the cost of providing contraception. The insurer would then cover the cost of the contraception coverage. But the plaintiffs said the letter made them complicit in the act of providing contraception – even if the insurers alone paid for it.

The court’s suggestion: What if nonprofits just made a blanket statement that they would not pay for contraception coverage? Then the insurer could step in to cover all such cases without involving the nonprofit. The plaintiffs agreed to the idea.

The peculiar circumstances of a divided 4-to-4 court changed what could have been a polarizing and partisan ruling into a rare moment of compromise.

Roberts has made attempts toward creating more unanimity on a divided court. The 2013-14 term was a microcosm of his efforts.

That year, roughly two-thirds of the court’s decisions were unanimous, the highest proportion since 1940. But they were not the most politically contentious cases. Roberts has promoted unanimity by pushing the court to take more “statutory” cases where the court largely agrees.

On the more controversial, “constitutional” cases, the nine justices dug into their ideological camps. These decisions centered on campaign finance, public sector unions, and whether some for-profit companies are exempt on religious grounds from providing contraceptives to employees. (The last decision that paved the way for the case the justices remanded on Monday morning.)

Welcome to the 5-to-4 era

The dynamic is the culmination of decades-long trends. The frequency of 5-to-4 decisions has risen steadily during the past century.

In the early decades, “5-4 decisions were few and unanimity was the rule,” according to a 1993 paper from Robert E. Riggs. From 1901 to 1910, only about 2.6 percent of cases were decided by a single vote, compared with about 23 percent of decisions in the 1980s. Since the mid-1990s the fraction of 5-to-4 and unanimous decisions has plateaued.

Roberts’s efforts to promote what some critics call “faux” unanimity means about 40 percent of the court’s decisions are unanimous. But the tenor of the court has been defined more by its 5-to-4 decisions.

To many, this is the way it should be. The court is not a venue for creating the artificial appearance of harmony.

In one unanimous opinion during the 2013-14 term, Scalia wrote: “I prefer not to take part in the assembling of an apparent but specious unanimity.”

But the court has acted that way in the past. Chief Justice Warren was famous for compelling the court to decide cases on narrow but consensus-building grounds as opposed to sweeping decisions that broke justices into partisan camps.

In the landmark racial case, Brown v. Board of Education, Warren went so far as to lobby one justice who planned to dissent, arguing that such a vital and controversial decision required unanimity. The justice agreed.

The current polarized political climate should compel the Roberts court to consider narrower, consensus-building moves like the one taken Monday, Professor Rosen says.

“By avoiding constitutionalizing an issue, or avoiding taking a strong stand on hotly-contested issue, the court is more likely to allow a consensus to materialize,” he says.

Should the court act this way?

Others question whether such an approach is realistic – or even in American democracy’s best interests.

“By the time a case gets to the Supreme Court, the issue is in such sharp focus and in such need of a resolution that a court decision would be a very good thing,” says Steven Schwinn, an associate professor at the John Marshall Law School.

“If they’re ruling on a case that will have an implication for future policymakers, future decision-makers, or even just future individuals, it’s important to step in and settle things and give some certainty to the law,” he says.

Because of its unique context, Monday's contraception case doesn't qualify as either true unanimity or "faux-nanimity." "Some might read [Monday's] ruling in the Zubik case as an attempt toward doing something that doesn’t reflect a sharply-divided court, that they’re doing something in the spirit of unanimity," says Schwinn. "But there’s no consensus on the merits."

But others see some scope for Monday’s decision to have a deeper effect on the court.

“If this turns out to lead to a compromise where the parties can agree, then it wouldn’t surprise me to see this happen more often,” says Susan Low Bloch, a professor at the Georgetown University Law Center.

“Unanimity is a fragile thing,” Rosen adds, but with the prospect of an eight-justice court for the remainder of the term – a term that will bring decisions on controversial issues from affirmative action to abortion access – he hopes that Monday’s experience could show justices a different way of working.

“The justices can choose to work together if they decide it’s in their interest, as they have now, or they can chose to join more sweeping and divided decisions,” he continues. “Now they’ve experienced both models, they’ll have a clearer choice moving forward.”